CODEWITHSUNDEEP
pythonmongodb
codious
codious

Reputation: 3511

mongodb keyerror even though field exists

I have a mongodb collection friends and I run the code

for doc in friends.find():
    print doc

I get: 

{u'_id': ObjectId('519ccdb86383cf1444445a1c'), u'twitter_id': 609034617}
{u'_id': ObjectId('519ccdb86383cf1444445a1d'), u'twitter_id': 253090547}
{u'_id': ObjectId('519ccdb86383cf1444445a1e'), u'twitter_id': 146221326}
{u'_id': ObjectId('519ccdb86383cf1444445a1f'), u'twitter_id': 1267350151}
{u'_id': ObjectId('519ccdb86383cf1444445a20'), u'twitter_id': 8806112}
{u'_id': ObjectId('519ccdb86383cf1444445a21'), u'twitter_id': 82589355}

but if I do:

for doc in friends.find():
    print doc['twitter_id']

I get the error:

Traceback (most recent call last):
  File "C:\Users\schatterjee\workspace\scorefollowback.py\application.py", line 65, in     <module>
    print doc['twitter_id']
KeyError: 'twitter_id'

Upvotes: 3

Views: 8978

Answers (1)

Tyler Brock
Tyler Brock

Reputation: 30136

Perhaps some of your documents don't have a twitter id. Here is an example shell session with good data:

>>> import pymongo
>>> conn = pymongo.MongoClient('localhost', 27017)
>>> users = conn['test']['users']
>>> users.remove()
>>> users.insert({'twitter_id': '11111111'})
>>> users.insert({'twitter_id': '22222222'})
>>> for user in users.find():
    ...     print(user['twitter_id'])
    ... 
    11111111
    22222222

You might want to try using $exists to make sure the field is present like this: Syntax: { field: { $exists: <boolean> } }

for friend in friends.find({ twitter_id: { $exists: true } }):
    print(friend['twitter_id'])

Upvotes: 1

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